In the statement, Bob and Jani Bergdahl say the letter, delivered through the International Committee of the Red Cross, gives them hope that their son is doing as well as can be expected, under the circumstances.

"He was scripted and redacted but he was no doubt alive and his faculties fully functioning as of two months ago," his father told a family friend, according to CBS affiliate KBOI. "They are being very careful with him. He is still highly valued at high levels."

They thanked the Red Cross for its help and support  and renewed their plea for his captors to release him.